Alternating-current motor.



H. F. HITNER. ALTERNATING CURRENT MOT OR.'

' APPLICATION FILED DEC. 24. 1906. 1,014,001,

. Patented Jan. '9, 1912 UNITED STA. 1 i

IHARRY FORD/IAN HI TNER, OF PITTSBURGH, PENNSYLVANIA, ASSIGIIQR TO BURKE ELECTRIC COMPANY, A CORPORATION OF PENNSYLVANIA.

ALTERNA'IING-CURRENT T/IOTOR.

Specification of Letters Patent.

Patented Jan. 9,1912.

Application filed December 24, 1906. Serial No. 349,235.

To all whom it may concern:

Be it known that I, HARRY F. Hirivnn, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Alternating-Current Motors, of which the following is a full, clear; and exact specification.

-My invention relates to automatic circuit changing means and particularly to means for starting alternating current motors.

In the particular application of my invention describedherein, I have shown and described the same as applied to starting a single phase motor of the induct-ion type but it will be understood that my invention is not limited to such application as various other applications thereof may be developed. Also my invention may be developed in various forms of apparatus other than that described herein.

It is well knownthat single phase induction motors are started with ditficulty and they are sometimes brought up to speed by extraneous means; but when once running at speed, the motor continues to run without difiiculty. By my invention the motor is started and brought up to a speed as a motor of one type and then operates as an induction motor of the usual type.

My invention will be understood from the following description and accompanying drawings in which Figure l is a side view of a motor embodying my invention with the circuit supplied with alternating current in diagram; Fig. 2 is a side view with parts of the rotor of the motor insection; and Fig. 3 is a diagram of the windings of the rotor.

Referring to Fig. l, the stator is represented as having the field frame 1 and two poles 2-, 2, excited by alternating current from a source 3. The rotor 4' is provided with windings of any of the usual types adapted for connectiomto a commutator. A winding of one such form is shown in Fig. 3 and is known generally as a lap winding. In this development the two poles are indicated in dotted lines at 5, 6. The windings are connected to an inner set of insulated contacts 7 in a manner similar to the usual conouter set of contacts 8, each of which is connected to one of the inner contacts located 180 degrees electrically therefrom; that is,

the contacts 8 are connected successively to the contacts 7 the relative location of a connected pair of contacts being approximately 180 degrees apart electrically. The two sets of contacts 7, 8 are shown in Fig. 2 as carried by and projecting through a drum 9 which'may be of insulating material or which maybe metal from which the contacts are insulated as indicated in the drawing. The inside of drum 9 is formed in anysuitable shape so as to retain a mobile conductive substance such as mercury 10.

In starting, the mercury 10 will of course, collect in the bottom of drum 9 and in this position will close connection between adja '7 cent contactsof {and 8 covered by the mercury. As the motor gradually attains speed, the mercury will gradually distribute itself over more and more of the inner periphery of drum 9, short circuiting more and more of contacts 7, 8. At full speed. all of the contacts will be short circuited giving many closed circuits of low resistance and the motor will then operate as an induction motor. While coming up,to speed, the motor acts as a repulsion motor. the circuits which are closed being so related in position to the poles 2, 2 of the stator that a resultant rotaiy effort in one direct-ion is produced due to the reaction upon the stator of the currents induced in said circuits.

In Fig. 3 the rectangle marked 10 repre sents the position of the mercury when the motor is at rest. It will be seen that the cir cuit through all of the rotor winding isclosed by the mercury joining certain contacts 7 to certain contacts 8 connected to the winding at points displaced proximately 180 de rees electrically. en the motor starts the mercury rem. i by action of gravity at the bottom of 9 and successively closes the circuit veen certain of the contacts 7, 8 which 1 rain the rotative effort by repulsion n 1* action of the windings. As the speec eases, the mer cury extends over moi" acts, short circuiting more coils until all speed all the contacts 7, 8 are covered by the mercury as above referred to and the motor then acts as aninduction motor. Thus the motor starts as a repulsion motor and. at full spee all of the winding is short circuited by thcmercury extending over all the contactsand the motor then, as ind motor. The

chines.

rapidity with which the mercury will be dis tributed over the whole cylindrical surface may be "controlled by variousfactors. For example if the cylindrical surface be made smooth and polished, a comparatively long interval will be required for the acceleration. If the surface be rough or have steps formed therein, the interval required for full distribution will be comparatively short and the acceleration more rapid. The.

diameter of the cylindrical member will also afiect .the time of distribution.

Although I have described a motor having two poles, it will be understood that any desired number of poles may be used and corresponding points in the winding may be cross connected if a multiple circuit winding be used. Also my invention may obviously be applied to other than single phase ma- It may sometimes be desirable to use other material than mercury, such as liquids or granules of various. conductive material. Also in order to reduce the sparking at contacts, it may be desirable to cover the Inercury with l quid such as oil 14, or to make oil.

' My invention "secures many advantages over prior apparatus such as in simplicity in construction reliability in operation and requiring little'or no ears or attention. Moreover, thez'pa'rts are easily accessible and renewable, v .LAlthough I have shown and described a form of my invention arranged to start as a repulsion motor and afterward run as an,

the cylinder aclosed chamber and fill withhaving a winding, and means comprising a fluent substance for connecting said winding to cause starting as a repulsion motor and for automatically changing connections upon increasein speed to cause running as an induction motor.

2. In an electric motor, the combination of a stationary element, a rotor having a winding, means comprising a fluent substance acted upon by gravity to cause connections'of said winding for starting asone type of motor and for automatically changlng connectlons upon increase in speed to cause running as a dlfl erent type of motor.

3. In. an electric motor, the combination of a stationary element, a rotor having a winding, connections from said winding, and a fluent substance acted upon by gravity for closing certain of said connections for causing starting as one type of motor and acted upon by movement of the rotor for closing certain of said connections for causing running as a different type of motor.

i. in an alternating current electric motor the comblnatlon or a stationary element, a rotorhavmg conductors, a fluent substance acted' upon by gravity for connecting said I conductors in one relationship with refer ence to eachiother and acted upon by a movement of the rotor for connecting said conductors in a difierent relationship with reference to each other.

5. In an alternating current motor, the combination of a stationary element, a rotor having conductors, a lfluent substance acted upon by gravity for connecting said conductors to cause operation as a repulsion motor and acted upon by centrifugal force to cause operation as an induction motor.

in testimony whereof I affix my signa ture, in presence or" two witnesses.

HARRY FURMAN Hrrnnn.

Witnesses: I

J. Pnovos'r, J; L. MERRILL. 

